fpsunflower

// c++ -o nanoexr nanoexr.cpp && ./nanoexr /tmp/foo.exr
#include <cstdio>

// writes a tiled OpenEXR file from a float RGB buffer
struct Exr {
    FILE* f; enum{TS=64}; ~Exr() { fclose(f); }
    void B(unsigned char i)      { fputc(i,f); }
    void I(unsigned int i)       { fwrite(&i,1,4,f); }
    void L(unsigned long long i) { fwrite(&i,1,8,f); }
    void F(float x)              { fwrite(&x,1,4,f); }

leibge

#!/bin/sh

# -------------------------------------------------------
# Run this script to create SSL certificates and files. 
# These will be generated into the "ssl" subdirectory of 
# the folder where this script file is located. 
# -------------------------------------------------------


#

jhclark

L1 cache reference                          0.5 ns
Branch mispredict                             5 ns
L2 cache reference                            7 ns             14x L1 cache
Mutex lock/unlock                            25 ns
Main memory reference                       100 ns             20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy              3,000 ns
Send 1K bytes over 1 Gbps network        10,000 ns    0.01 ms
Read 1 MB sequentially from memory      250,000 ns    0.25 ms
Round trip within same datacenter       500,000 ns    0.5  ms
Read 1 MB sequentially from SSD       1,000,000 ns    1    ms  4X memory

marianposaceanu

CPU

• L1 cache reference 0.5 ns
• Branch mispredict 5 ns (on a bad CPU architecture you're pretty much screwed)
• L2 cache reference 7 ns
• Mutex lock/unlock 25 ns
• Main memory reference 100 ns
• Compress 1K bytes with Zippy 3,000 ns
• Send 2K bytes over 1 Gbps network 20,000 ns
• Read 1 MB sequentially from memory 250,000 ns

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD